| 摘要 |
PURPOSE:To reduce internal stress when a Josephson structure is formed, by making a seat, which is formed on a substrate, thick, and making a lower superconducting layer formed thereon thin. CONSTITUTION:A seat forming material layer 21 is evaporated on the entire surface of a silicon substrate 20. Etching is performed in accordance with a pattern arranged on a horizontal plane. a seat 22 is formed at a specified position, where each Josephson element is formed. Nb is sputtered, and a lower superconducting layer 31 is formed. An Al film is sputtered thereon. Then oxygen is introduced, and Al2O3 film is formed. Thus a tunnel-barrier forming insulating layer 32 is obtained. After the oxygen is exhausted, Nb is further sputtered on the Al2O3 film, and an upper superconducting layer 33 is formed. Thus a Josephson junction structure 34 is obtained. A photoresist layer is attached on the upper surface of the upper superconductive layer 33. a remaining resist part 40 is made to remain, and the other part of the Josephson junction structure 34 undergoes dry etching. Thus a Josephson element 60 comprising a lower electrode 50, a tunnel barrier 51 and an upper electrode 53 is obtained. |
